Method and device for protecting text for reading

ABSTRACT

A method and a device for protecting text for reading ( 23 ), arranged on at least one written face ( 22 ) of an object ( 25 ). The object ( 25 ) is connected to at least one matching antenna ( 12 ), produced by printing on a support ( 11 ) and having at least one electromagnetic coupling zone ( 14 ) with an individual antenna of smaller dimensions. At least one security film ( 3 ), not provided with a matching antenna ( 12 ) but with at least one individual integrated antenna microcircuit called a microtransponder ( 7 ), is applied to cover the text for reading ( 23 ) for which authentication information may be delivered using the microtransponder ( 7 ).

The invention relates to the protection of readable script formed on aface of an object such as an official document.

In many applications, it is necessary for script formed earlier onobjects to be protected against forgery and/or for the purpose ofauthentication and/or in order to guarantee its integrity.

One known solution (for example EP-0271941 or U.S. Pat. No. 5,232,527)consists in covering the readable script with a transparent film (thatis to say a film making it possible to read the script that it covers)which adheres to the object and has a free outer face after having beenplaced on the object.

The object may, for example, be an official document (passport, visa,identity card, driver's license, bank card, access control card, passes,tags, judicial document, survey map, manufacturing schematic or otherdiagram, etc.) bearing readable script such as variable records (name,first name, address, photograph, etc. of a bearer or of the parties,etc.) and/or common records (security designs, registers, lists, fieldnames, seals, holograms, etc.) to be protected against forgery and/orfor the purpose of authentication and/or in order to guarantee itsintegrity (that is to say that it has not been tampered with ormodified). The object may also be packaging, a product or article of anytype bearing readable script which needs to be protected, such as text,a logo, drawing, photograph, serial number, etc.

Throughout the text, the term “readable script” will be used to mean anysign or pattern formed on the document, which can be read by a person atleast under certain conditions (in particular under normal illuminationwith visible light; and/or under specific illumination; and/or afteractivating an electronic device (screen) or the like, etc.) which may beat least partially represented by recordable digital data. This mayinvolve text (handwriting or printed characters); codes (ASCII,universal optoelectronically read codes such as barcodes, etc.); imagesor photographs, etc.

Integrated circuit memory devices (chips) are furthermore known whichhave a contactless information transmission link, in particular forreading, making it possible to associate personalized informationsecurely with objects such as bank cards, electronic passes, electronictags, etc. WO 02/21436 envisages the integration of a contactless chipwith a document for identifying a physical individual, in particularwhen the document is being personalized, for example by integrating itin a security film or sandwiching it between laminated layers of thedocument. This document does not indicate how such a chip can beproduced and does not explain how this contactless chip could inpractice be integrated with a security film. Moreover in view of thethickness of such a chip, the problems linked to electrical connectionof the integrated circuit with the associated antenna(s) and theprohibitive size of the antenna needed in order to obtain coupling witha reader at a sufficient range with respect to the space available onthe document, the cited variant of integration with a security film isnot practically viable in the light of this document.

Sandwiched incorporation of the chip between two sheets of the documentis also expensive and poses practical manufacturing problems. There isin particular a risk that such a chip, which is relatively fragile, willnot withstand the process of printing the personalization script. If itis associated with the document after this printing, such association iscomplex and not very reliable.

In any event, a chip incorporated with a document by sandwiching isphysically disassociated from the readable script, so that tamperingwith the chip and with the readable script may be carried outindependently.

It should also be noted that if a contactless chip and its antenna havesmall dimensions, this entails a short reading range. It is furthermorenecessary to place the chip very precisely with respect to a readingdevice—in particular with respect to the axis of the antenna of thisreading device.

Furthermore, FR-2 812 482 or EP-0826190 describe contactless deviceshaving chip(s) with magnetic coupling between two antennas, one of whichis an antenna coil electrically connected to the integrated circuit ofthe chip—in particular of the “coil on chip” type—and one is a passiveantenna coil of larger dimensions, making it possible to increase thereading range of the chip with less bulk. The two antennas may bemagnetically coupled by means of a coupling loop which is formed by thelarge coil, and whose dimensions correspond to those of the small coil.FR-2 812 482 mentions that the large coil may be incorporated in thethickness of the cover of a booklet, each page of which holds one ormore contactless micromodule(s) (chip with its integrated antenna (smallcoil)) fixed on a plastic sheet arranged in a booklet. These devices donot provide a solution to the problem of protecting readable scripteffectively, in particular against forgery and/or for the purpose ofauthentication and/or in order to guarantee its integrity. Inparticular, the chips themselves are unprotected and may be corrupted oreven replaced by a forger. Placing them on each page of the booklet isexpensive and complicated, especially if coupling of the type describedby EP-0826190 is envisaged. Furthermore, incorporating an antenna withlarge dimensions in the thickness of the cover is expensive and, sinceit makes this antenna invisible, does not allow precise subsequentpositioning of each chip with respect to this antenna. Yet this precisepositioning is indispensable in order to obtain sufficient magneticcoupling.

It should also be noted that the solution described in FR-2 812 482 doesnot in practice offer effective coupling of each individual antenna withthe group antenna.

The prior art thus does not provide an economical, simple and reliablesolution, compatible with practical implementation on an industrialscale, which makes it possible for an electronic memory device havingmicrocircuit(s) with contactless reading, referred to as a contactlesschip, to be associated effectively with an object bearing readablescript, with a view to protecting this readable script.

It is a general object of the present invention to resolve this problem.

More particularly, it is an object of the invention to prevent the riskof the contactless chip masking the readable script, and to offer asufficient reading range of the contactless chip—in particular of theorder of several centimeters—and a low lateral positioning precision ofthe object and the contactless chip with respect to a reading device—inparticular of the order of several millimeters or even severalcentimeters.

It is also an object of the invention to provide protection of thescript in which a contactless chip is combined with a transparentprotective film, insofar as the contactless chip reinforces theprotection provided by the film and the security film reinforces theprotection provided by the contactless chip. In this regard, it is moreparticularly an object of the invention to permit the effectiveincorporation of a contactless chip in a transparent protective film, inparticular as described in EP-0271941 or U.S. Pat. No. 5,232,527, withthis film protecting the chip itself, and the use of this combinationfor the protection of readable script.

More particularly, it is an object of the invention to obtain suchprotection by implementing only simple steps of adhesively bondingfilm(s) and/or printing, in particular without the need to incorporatean element within a thickness of paper or card, or sandwiched betweentwo sheets of paper or card.

It is also an object of the invention to permit simple and rapidimplementation of the protection method, in particular so that precisepositioning of the various elements is readily obtained without complextechnology.

In this regard, it is in particular an object of the invention toprovide protection which can be used by local administrations forissuing official documents (for example identity cards, passports,driver's licenses, visas, etc.) or during the industrial manufacture ofpackaging, products or articles, without requiring the use of complex,heavy and expensive equipment.

Throughout the text, the term “antenna” generally denotes anyelectrically conductive line making it possible to produceelectromagnetic—especially inductive and/or magnetic—coupling withanother electromagnetic device. The term “electromagnetic coupling”denotes any form of remote coupling by means of electric and/or magneticand/or electromagnetic field(s). Furthermore, the term “microcircuit”denotes any device with a size of less than 5 mm×5 mm×5 mm forming anelectronic circuit, which is produced essentially according tointegrated circuit technologies. It may in particular be a chip with amemory (ROM, RAM, EPROM, flash, etc.) and/or with a microprocessorand/or with hardwired logic, optionally provided with othernonelectronic or secondary functions (antenna), or a plurality of chipsassociated in order to form such a device.

The invention therefore relates to a method for protecting readablescript formed on at least one face of an object, referred to as ascripted face, in which readable script on at least one scripted face ofthe object is covered with a transparent protective film referred to asa security film, which adheres to this scripted face, and the object isassociated with at least one microcircuit having at least one antennafor contactless remote reading of authenticating information, which canbe delivered by this microcircuit and is designed to permitauthentication of at least some of the readable script,

wherein:

-   -   the object is associated with at least one antenna referred to        as a matching antenna, formed by printing on a support, this        matching antenna having at least one zone for electromagnetic        coupling with an individual antenna whose dimensions are smaller        than those of the matching antenna,    -   at least one film referred to as a security film is used, which        does not carry a matching antenna but carries at least one        microcircuit with an integrated individual antenna, referred to        as a microtransponder, at a predetermined position so that after        the security film has been placed on a scripted face of the        object, and for at least one position or state of the object:        -   it permits electromagnetic coupling of the individual            antenna with an electromagnetic coupling zone of a matching            antenna associated with the object,        -   it does not mask any essential part of the readable script,    -   a security film is applied and adhered to a corresponding        scripted face in order to cover readable script and so as to        permit electromagnetic coupling of the individual antenna of        each microtransponder with a coupling zone of a matching        antenna, for at least one position or state of the object, the        matching antenna having dimensions designed to permit the remote        transmission of information between the individual antenna and a        power antenna of a reading device when the object is placed in        the field of this power antenna.

The invention extends to a device for carrying out a method according tothe invention. The invention therefore relates to a device forprotecting readable script formed on at least one face of an object,referred to as a scripted face, comprising:

-   -   at least one transparent protective film referred to as a        security film, which is intended to adhere to a scripted face        while covering readable script, and    -   at least one microcircuit intended to be associated with the        object, having at least one antenna for contactless remote        reading of authenticating information, which can be delivered by        the microcircuit and is designed to permit authentication of at        least some of the readable script, which comprises:    -   at least one antenna intended to be associated with the object,        referred to as a matching antenna, formed by printing on a        support and having at least one zone for electromagnetic        coupling with an individual antenna whose dimensions are smaller        than those of the matching antenna,    -   at least one film referred to as a security film, which does not        carry a matching antenna but carries at least one memory        microcircuit with an integrated individual antenna, referred to        as a microtransponder, at a predetermined position so that after        the security film has been placed on a scripted face of the        object, and for at least one position or state of the object:        -   it permits electromagnetic coupling of the individual            antenna with an electromagnetic coupling zone of a matching            antenna associated with the object,        -   it does not mask any essential part of the readable script,            and wherein the matching antenna has dimensions designed to            permit the remote transmission of information between the            individual antenna and a power antenna of a reading device            when the object is placed in the field of this power            antenna.

The coupling zone and the individual antenna have similar dimensions,corresponding at least substantially to the script or smaller than thisscript, so that the individual antenna does not mask the script.Advantageously and according to the invention, the area of a couplingzone of an individual antenna and of a microtransponder is less than 10mm². The coupling zone is thus much smaller than the matching antenna,the dimensions of which may correspond at least substantially to thoseof the size of the object.

The electromagnetic coupling should occur for at least one position orstate of the object, in which the relative positions of the couplingzone of the matching antenna and the individual antenna are such thatthe electromagnetic coupling takes place. In particular, advantageouslyand according to the invention, the matching antenna and the securityfilm are in relative positions designed so that the coupling zonelocated on the matching antenna faces the individual antenna. It may bethat the electromagnetic coupling does not take place in certainpositions of the object or in certain states of the object. In the caseof an object formed by a booklet, a book or a plurality of sheets, forexample, the electromagnetic coupling may be obtained only when thesheets or pages are against one another, that is to say when the bookletor pamphlet is closed.

Being carried by a security film, each microtransponder is definitivelyprotected by this security film, on the one hand from mechanical harmand on the other hand from attempted forgery. In particular, since thesecurity film is necessarily put on after the readable script has beenformed, the microtransponder(s) is/are not subjected to the steps ofprinting the script.

It should be noted that in contrast to that which WO 02/21436 provides,the electromagnetic memory device for the recording of authenticatinginformation in a method and a device according to the invention is notnecessarily incorporated entirely in the security film which covers thereadable script. In particular, the matching antenna which makes itpossible in practice to obtain a suitable reading range and asufficiently small lateral positioning precision is printed on a supportand is not incorporated in a thickness of a cover of the object, made ofa sheet of paper or card. Also, since each microtransponder is preciselyplaced with respect to a security film, a simply precise placement ofthe security film on the object (a traditional operation which is easyto carry out, even manually) makes it possible to ensure preciserelative positioning of each individual antenna of this security filmwith respect to a coupling zone of the matching antenna. This simplefact leads to great ease of manufacture and use.

The (individual and matching) antennas are designed to permit at leastcontactless reading. They may also permit contactless writing to thememory. As a variant, the writing may be carried out via another link,with or without contact.

With the invention, furthermore, a security film bearing at least onemicrotransponder and not a matching antenna covers the readable scriptfor at least one scripted face of the object. This disassociationsignificantly reinforces the protection against forgery. It also makesit possible to protect a scripted face that does not have enough freespace to incorporate a matching antenna.

Advantageously and according to the invention, at least one matchingantenna is printed on a face of the object which may or may not be ascripted face in the context of the invention, that is to say one whichbears readable script needing to be protected by the recording ofcorresponding information in a microtransponder. After printing theprinted matching antenna, advantageously and according to the inventionit is subsequently covered with a protective film, in particular asecurity film if the matching antenna is printed on a scripted face.

In a preferred variant, advantageously and according to the invention,at least one matching antenna is printed on or in (incorporated betweena plurality of layers of) a film of synthetic material referred to as anantenna film, and is carried by this antenna film. The antenna film isadhered to a face of the object.

This antenna film may be a security film carrying at least onemicrotransponder, which may be connected to the matching antenna, withthe overall circuit that is formed fulfilling both functions (at leastone other security film without a matching antenna is then provided).The matching antenna may also constitute a main antenna for amicrotransponder, to which it is electrically connected; and act as amatching antenna for one or more microtransponder(s) associated with oneor more security film(s) separate from the antenna film. As a variant,the antenna film is not a security film (that is to say it does not havea microtransponder). Thus, advantageously and according to theinvention, the matching antenna in this variant is printed on a printingsupport which is not a security film carrying at least onemicrotransponder.

Advantageously and according to the invention, the antenna film isapplied and adhered to a face of the object which is not a scriptedface—in particular to a face of the object which is the verso of a sheetof the object whose recto is a scripted face. By virtue of theinvention, therefore, the readable script is protected on the recto of asheet which carries it by a security film carrying at least onemicrotransponder, and on the verso of this film by an antenna filmwhich, like the security film, may also be a thin film for protectionagainst attempted forgery. The security film and/or the antenna filmadvantageously incorporate(s) means which reinforce the protectionagainst attempted forgery and/or authentication (photoluminescentpatterns, soluble inks, patterns whose appearance varies depending onthe direction of illumination and/or reading, holograms, anti-photocopypatterns, weakened areas, differential adhesion of a plurality of layersin contact, etc.). Attempted forgery either through the recto or throughthe verso of the sheet is therefore bound to fail.

Moreover, advantageously and according to the invention, at least onematching antenna is printed with an ink which is transparent to visiblelight and electrically conductive after drying. For example, atransparent ink composition is used which incorporates at least onetransparent electrically conductive polymer compound such as apolythiophene—in particular a PEDT/PSS mixture. In this way, thematching antenna is invisible or not very visible, and it may beassociated overlapping with readable script on the object. As a variantor in combination, at least some of a matching antenna may form apattern that itself constitutes one (or more) readable scripts. In thisway, this pattern formed by the matching antenna cannot be distinguishedfrom the readable script lying underneath.

Furthermore, advantageously and according to the invention, at least onetransfer referred to as an antenna transfer is used, comprising asupport sheet carrying an adhesive antenna film, this antenna transferbeing designed to make it possible to apply and adhere the antenna filmto a face of the object by separating the antenna film from the supportsheet. Advantageously and according to the invention, such an antennatransfer is a cold dry transfer (the adhesive being of the typesensitive to pressure when cold, that is to say at room temperature) or,as a variant, a hot transfer (the adhesive being of the heat sensitivetype). Such transfers can be used in a straightforward andwell-controlled way.

Advantageously and according to the invention, at least one matchingantenna forms a resonant electrical circuit comprising an inductor andan electrical capacitor. Advantageously and according to the invention,at least one matching antenna comprises an electrical capacitor ofadjustable value. This value can be adjusted before placement, forexample, so as to make it possible to obtain a good match of thematching antenna to each associated microtransponder, and to do so withjust one type of matching antenna. For instance, the matching antennamay be produced in a standardized form and is tuned during use in a waywhich may be predefined, according to the number of associatedmicrotransponder(s) and the nature of each associated microtransponder.

Since the matching antenna is printed, the same will be true of thiscapacitor formed by two conductive layers printed facing each other inorder to form two capacitor plates separated by a printed insulatorlayer, at least one of the plates being in the shape of a comb whoseteeth can be cut, for example by scratching, so as to modify its activearea. The value of the electrical capacitor can thus be determined andtuned before the power antenna is produced. Furthermore, this electricalcapacitor may also be incorporated in a graphic pattern of the antennafilm and/or of the object, or superimposed with such a pattern, so thatit is difficult to detect.

Furthermore, advantageously and according to the invention, at least onematching antenna is printed by silkscreen printing.

Advantageously and according to the invention, at least one givenmatching antenna is used comprising a plurality of electromagneticcoupling zones for coupling it with a plurality of individual antennasof a plurality of microtransponders belonging to the same security filmor to a plurality of security films associated with different scriptedfaces. Advantageously and according to the invention, a plurality ofsecurity films each comprising at least one—in particular asingle—microtransponder is used for the protection of readable script ona plurality of scripted faces of the object. Advantageously andaccording to the invention, a single matching antenna is used for theobject. For example, a single matching antenna may be provided for theprotection of an official document such as a passport in the form of abooklet or pamphlet.

Moreover, advantageously and according to the invention, at least onesecurity film comprising at least one microtransponder incorporated inits thickness is used. Advantageously and according to the invention, atleast one multilayered security film is used. Advantageously andaccording to the invention, at least one security film formed byprinting is used, incorporating at least one microtransponder in thethickness of the security film when the security film is being formed byprinting, between two printed layers. The microtransponder can thus beintegrated between a plurality of varnish and/or adhesive layers of thesecurity film. Advantageously and according to the invention, at leastone security film formed by silkscreen printing is used.

Advantageously and according to the invention, each microtransponderincorporated with a security film has a thickness of less than 0.2 mmand an area of less than 10 mm² in the plane of the security film.Advantageously and according to the invention, each microtransponderincorporated in a security film has a thickness of between 50μ and 180μ.

Furthermore, advantageously and according to the invention, at least onetransfer referred to as a protection transfer is used, comprising asupport sheet carrying an adhesive security film, this protectiontransfer being designed to make it possible to apply and adhere thesecurity film to a scripted face of the object by separating thesecurity film from the support sheet. Advantageously and according tothe invention, such a protection transfer is a cold dry transfer or, asa variant, a hot transfer.

Moreover, advantageously and according to the inventon, information forauthenticating at least some of the readable script isrecorded—especially in an encrypted form—in at least one memory of atleast one microtransponder carried by at least one security filmcovering readable script. As a variant or in combination, advantageouslyand according to the invention, at least authenticating informationwhich represents a key and/or an algorithm for authentication and/or acertificate resulting from an algorithm is recorded in at least onememory of at least one microtransponder. This recording is carried outin an irreversible form, that is to say it is not subsequently possibleto erase or modify the recorded information. This recording may takeplace before or after the security film and/or the matching antenna isplaced on the object. As a variant or in combination, advantageously andaccording to the invention, at least one microtransponder forming alogic circuit is used.

The invention also relates to a device which comprises at least onematching antenna and/or at least one antenna transfer and/or at leastone security film and/or at least one protection transfer as mentionedabove.

The invention extends to an object comprising readable script protectedby a method according to the invention and/or with a device according tothe invention. The invention therefore relates to an object comprisingat least one face referred to as a scripted face on which readablescript is formed, which comprises:

-   -   at least one matching antenna formed by printing on a support        and associated with the object, this matching antenna having at        least one zone for electromagnetic coupling with an individual        antenna whose dimensions are smaller than those of the matching        antenna,    -   at least one security film which does not carry a matching        antenna but carries at least one microcircuit and with an        integrated individual antenna, referred to as a        microtransponder, the security film being applied and adhering        to a scripted face in order to cover readable script, the        position of each microtransponder being designed so as to permit        electromagnetic coupling of the individual antenna of each        microtransponder with a coupling zone of a matching antenna, for        at least one position or state of the object, the matching        antenna having dimensions designed to permit the remote        transmission of information between the individual antenna and a        power antenna of a reading device when the object is placed in        the field of this power antenna, and wherein at least one        microtransponder of a security film covering readable script is        designed to be able to deliver information for authenticating at        least some of this readable script.

The invention also relates to a method, a device and an object which incombination have some or all of the features mentioned above or below.

Other objects, features and advantages of the invention will becomeapparent on reading the following description, referring to the appendedfigures which represent nonlimiting exemplary embodiments of theinvention and in which:

FIG. 1 is a schematic sectional view of a protection transfer of adevice according to the invention,

FIG. 2 is a schematic sectional view of an antenna film of a deviceaccording to the invention,

FIG. 3 is a schematic sectional view illustrating a method according tothe invention for protecting a sheet of a document with the aid of theprotection transfer in FIG. 1 and the antenna film in FIG. 2,

FIG. 4 is a schematic exploded perspective view of the protected sheetobtained by the method according to the invention corresponding to FIG.3,

FIGS. 5 and 6 are similar views to FIG. 3, respectively illustrating twoalternative embodiments of the invention,

FIG. 7 is a schematic perspective view of a document, such as apassport, protected by a method according to the invention,

FIG. 8 is a schematic perspective view of an embodiment detail of anelectromagnetic coupling zone of a matching antenna of a deviceaccording to the invention,

FIG. 9 is a schematic perspective view of an embodiment detail of anadjustable capacitor of a matching antenna of a device according to theinvention,

FIG. 10 is a schematic perspective view illustrating the use of adocument protected according to the invention.

In the figures, the thicknesses have been exaggeratedly enlarged forillustration purposes.

The protection transfer 1 represented in FIG. 1 comprises a supportsheet 2 on which a transparent adhesive security film 3 is printed. Inthe example which is represented, this security film 3 comprises twocontinuous printed polyurethane layers 4, 5 (in the format of thesecurity film 3 formed in this way) between which at least one securitypattern 6 is printed. The security film 3 is a multilayered film whichmay be produced, for example as described in EP 0271941 or U.S. Pat. No.5,232,527, by successively printing layers whose composition polymerizesafter printing. The support sheet 2 is made of polystyrene, for example,in order to permit subsequent separation of the security film 3 bytransfer onto an object. The first polyurethane layer 4 issilkscreen-printed onto the support sheet 2. Before the end of thepolymerization, the security pattern 6 is silkscreen-printed onto thisfirst layer 4 then a memory microcircuit (chip) with an integratedantenna (that is to say of the “coil on chip” type) referred to as amicrotransponder 7 is adhesively bonded. Still before the end of thepolymerization of the first layer 4, the second continuous polyurethanelayer 5 is silkscreen-printed. A continuous adhesive layer 8 which is anadhesive sensitive to cold pressure (self-adhesive) or a heat sensitiveadhesive is subsequently printed, likewise by silkscreen printing. Theadhesive is covered with a nonstick protective sheet 9, for example madeof silicone paper.

The selected microtransponder 7 is for example an IC-Link® PicoPass® orIC-Link® MicroPass® chip marketed by INSIDE TECHNOLOGIES (FRANCE).

The microtransponder 7 whose overall thickness is more than that of thelayers 4, 5 (in the figures, the thicknesses are not true to scale andthe relative thicknesses are not represented realistically) may becovered with a thin film wafer, or may even be carried by a film waferin the manner of a tag, equipped with reference markers in order to makeit easier to place it on the first layer 4 then form the second layer 5.

After having positioned this microtransponder 7, the second polyurethanelayer 5 and the adhesive layer 8 are printed using a flatbed silkscreenprinting machine with a plane screen having a suitable value of angularor flat lift, making it possible to avoid friction of the squeegee andthe screen as the microtransponder 7 passes. The use of a silkscreenprinting technique thus makes it possible to avoid applying a pressureroller to the microtransponder 7. Notwithstanding, other printingtechniques could also be used while taking care to avoid any damage tothe microtransponder 7, either by exerting sufficiently small pressuresor by providing the pressure members with gaps or recesses toaccommodate the microtransponder 7.

FIG. 2 represents an antenna film 10, also formed by successivesilkscreen printing on a support sheet 11, for example made ofoptionally transparent polyester.

A matching antenna 12 in the overall shape of a large loop 15 with largedimensions forming an electrical inductor, which is for examplerectangular, that is to say a passive inductive antenna, issilkscreen-printed onto this support sheet 11. An electricallyconductive ink composition is used, for example a conductive silver inkreference 5028 marketed by DUPONT DE NEMOURS (USA).

The matching antenna 12 also comprises an electrical capacitor 13. Itthus constitutes a resonant circuit and may be referred to as a“resonator”. The electrical capacitor 13 is formed by two layers 13 a,13 b of conductive ink superimposed to form two facing plates separatedby a layer 13 c of insulating varnish. The matching antenna 12 alsocomprises at least one loop 14 for electromagnetic coupling with anantenna of a microtransponder 7. This electromagnetic coupling loop 14has small dimensions, much less than those of the large loop 15 formedby the matching antenna 12 and corresponding to those of the integratedantenna of a microtransponder 7. It is formed by a small square turnproduced on a branch or in a vertex of the large loop 15.

FIGS. 8 and 9 respectively illustrate an embodiment of anelectromagnetic coupling loop 14 and an electrical capacitor 13. A lowerfirst track of conductive ink is printed first, forming a half 15 a ofthe large loop 15, an open square lower loop 14 a of the coupling loop14 and a lower plate 13 a of this capacitor. An electrically insulatingvarnish composition is then printed, for example a cutting basereference UVIPRIM CV marketed by TIFLEX (FRANCE) forming an insulator 14c of the coupling loop 14, partially covering the open lower loop 14 aapart from its end portion 17 a; and a layer 13 c of insulator coveringthe plate 13 a of the capacitor 13. An upper second track of conductiveink is then printed, forming the second half 15 b of the large loop 15,an open square upper loop 14 b of the coupling loop 14, superimposedwith the lower loop 14 a and with the insulator 14 c, the end part 17 bof this upper loop 14 being electrically connected to the end part 17 aof the lower loop 14 a. The upper second track also forms an upper plate13 b of the capacitor 13, superimposed with the lower plate 13 a via thelayer 13 c of insulator. The upper plate 13 b is preferably in the shapeof a comb, that is to say it has parallel teeth 19 of similar ordifferent widths extending from a common longitudinal strip 18 andcapable of being insulated from this strip 18 after the matching antenna12 is printed, by scratching their initial portion connecting to thisstrip 18. FIG. 4 represents two teeth 19 whose initial portions 29 havebeen scratched, so that these two teeth are separated from the upperplate 13 b. It is thus possible to adjust the value of the electricalcapacitor 13 formed between the plates 13 a, 13 b.

A continuous layer of adhesive 20 is printed over the matching antenna12, and this may be covered with a nonstick sheet 21 such as siliconepaper. In order to make it possible to adjust the capacitor 13 byscratching at the time of use, an opening (not shown in the figures) maybe formed through the adhesive 20 in order to make it possible to accessthe initial portions of the teeth 19 of the upper plate 13 b and scratchthem. In the example which is represented, the large loop 15 of thematching antenna 12 forms a closed electrical circuit having a singleturn. As a variant (not shown) the large loop 15 of the matching antenna12 may comprise a plurality of turns, either juxtaposed in the sameplane, wound in one another or superimposed with one another via layersof insulating varnish, or juxtaposed, wound and superimposed. Thisincreases the value of its electrical inductance. Likewise, the couplingloop 14 may be formed by a plurality of juxtaposed, wound and/orsuperimposed turns. The number of turns of the large loop 15 is notnecessarily the same as that of the coupling loop 14. The electricalcapacitor 13 may also comprise more than one pair of plates 13 a, 13 bconnected in series (superimposed) or in parallel (juxtaposed).

In any event, an antenna sheet 10 (support sheet 11, matching antenna 12and adhesive 20) covered with a nonstick sheet 21 is obtained.

FIGS. 3 and 4 represent the object to be protected in the form of arectangular sheet 25 (passport page; identity card, etc.) at least oneface 22 of which, referred to as a scripted face 22 and assumed to bethe recto of the sheet, bears readable script 23, for example aphotograph 24, common records, variable records (name, first name,address, signature, digital or optically read codes, etc.) or the like.

The format of the security film 3 is preferably designed to cover thescripted face 22 entirely. There is nothing to prevent a smaller formatbeing provided, however, with the security film 3 covering readablescript 23 only over a part of the surface of the scripted face 22.

The matching antenna 12 may be associated with the verso of the sheet25, that is to say on its face 26 on the other side from the scriptedface 22. The matching antenna is preferably selected to have a shapecorresponding at least substantially to that of the sheet 25, and so asto extend close to the periphery of the face 26 of this sheet 25. Thisis because the large loop 15 is then as large as possible.

The microtransponder 7 is placed in the security film 3 so that it issubsequently as discreet as possible (after placement on the scriptedface). Furthermore, the microtransponder 7 may be superimposed with apattern of the scripted face, so that it merges within this patternwithout being readily detectable by observation. The position of themicrotransponder 7 is thus chosen so that it faces a correspondingcoupling loop 14 after placement in order to ensure their relativeelectromagnetic coupling, that is to say in order to make it possible toread the information recorded in the memory of the microtransponder 7via the coupling loop 14 and the matching antenna 12. It should be notedthat these precise relative positions are actually obtained during themanufacture of the antenna film 10 and of the security film 3. After thereadable script 23 has been formed on the scripted face 22, it issufficient to put the two films 10, 3 in place, one 3 on the recto andthe other 10 on the verso of the sheet 25, in order to ensure correctrelative positioning of the microtransponder 7 vis-á-vis the couplingloop 14. The face 26 of the sheet 25 which receives the matching antenna12 may also carry readable script 27, such as security patterns or thelike. The security film 3 is put on by transfer. The nonstick sheet 9 isremoved and the adhesive 8 is applied to the scripted face 22. Thesupport sheet 2 is detached after activation of this adhesive 8. Thisleaves only the transparent thin film 3 formed by the two polyurethanelayers 4, 5 within which microtransponder 7 is incorporated, and theadhesive layer 8. The nontransparent microtransponder 7 occupies only avery small part of the surface of the security film 3, and is thereforevery discreet. The microtransponder 7 is thus incorporated between thescripted face 22 of the object and the free outer face of the securityfilm 3.

The adhesive layer 20 of the antenna film 10 is applied to the face 26in order to associate this antenna film, and therefore the matchingantenna 12, with the sheet 25. The antenna film 10 is transparent or notdepending on whether or not the support film 11 is transparent.

FIG. 5 represents an alternative embodiment in which the matchingantenna 12 is incorporated within a multilayered thin film 30, forexample similar to the security film 3 described above and as describedby EP 0271941 or U.S. Pat. No. 5,232,527. The matching antenna 12 may besilkscreen-printed between the two continuous varnish layers of thisantenna film 30, which is capable of being produced in the form of atransfer referred to as an antenna transfer 31. The antenna film 30 isprinted onto the polystyrene support sheet 32. It comprises a finaladhesive layer 33 which can be applied against the face 26 of the sheet25 to be protected. The support sheet 32 may be removed after activationof the adhesive 33 and transfer.

It should be noted that (variant not shown) the format of the securityfilm 3 and of the antenna film 10, 30 may be larger than that of thesheet 25, so that the latter is then entirely enclosed and integrated ina pouch formed between and by these two films 3, 10, 30 whose peripheralborders are adhesively bonded together.

FIG. 6 represents another variant, in which the matching antenna 12 isprinted directly onto the face 26 (verso) of the sheet 25 to beprotected, for example by silkscreen printing. This antenna maysubsequently be covered with an optionally transparent, optionallymultilayered protective film 35 optionally produced in the form of atransfer (printed onto a detachable support sheet 36 as represented inFIG. 6), which is provided with an adhesive layer 37 for adhesivelybonding it onto the face 26 over the matching antenna 12 printedearlier.

As a variant (not shown) if the available space permits this, thematching antenna 12 could be printed directly onto the scripted face 22around and beside the readable script 23. If a transparent conductiveink composition is used (incorporating a sufficient proportion oftransparent conductive polymer such as BAYTRON P® marketed by BAYER AG,GERMANY or described in EP-593111 or EP-602713, in a transparentprinting base) the matching antenna 12 is sufficiently transparent topermit reading through it, and it may be printed or applied so as tooverlap readable script 23.

A given security film 3 may incorporate a plurality of microtransponders7 (variant not shown). The protective device may also comprise aplurality of security films 3, if the object has a plurality of scriptedfaces to be protected. A plurality of power antennas 12 may be provided,for example one for each sheet of the object to be protected.Preferably, however, as represented in FIG. 7 in the case of an objectin the form of a booklet 40 with a plurality of sheets 25 a, 25 b, 25 c,25 d (for example a passport) it is possible to provide a plurality ofsecurity films 3 a, 3 b, 3 c and a single matching antenna 12, which isprovided with a plurality of coupling loops 14 a, 14 b, 14 c that arelaterally offset from one another. Each security film 3 a, 3 b, 3 ccomprises a microtransponder 7 a, 7 b, 7 c. These microtransponders 7 a,7 b, 7 c are offset so as to respectively face the coupling loops 14 a,14 b, 14 c when the booklet 40 is closed with its sheets 25 a, 25 b, 25c, 25 d superimposed. The matching antenna 12 is carried by an antennafilm 10 applied to one of the faces of a sheet 25 d, which may or maynot be a cover of the booklet 40. In the example which is represented,merely for illustration purposes, the security films 3 a, 3 b, 3 c areadhesively bonded onto scripted faces 22 a, 22 b, 22 c oriented in thesame direction. The other faces of the sheets 25 a, 25 b, 25 c, 25 d mayalso be scripted faces which receive a security film with one or moremicrotransponder(s).

A plurality of embodiments may be envisaged in respect of themicrotransponder 7 and its use. The microtransponder 7 may be a memorymicrocircuit. Authenticating information may in this case be recorded inthe memory of the microtransponder 7, preferably in an encrypted formand irreversibly, particularly in a read-only memory as is well-knownper se. This recording may be carried out via the matching antenna 12and thus be facilitated. This authenticating information may consist ofsome or all of the readable script 23 and/or a key and/or an algorithmfor reading other information recorded in the microtransponder 7, or ina database recorded on a separate computer system. For instance, themicrotransponder 7 may record digital data representing readable scriptand/or instructions that can be carried out by a microprocessor of themicrotransponder 7 in order to perform an algorithmic calculation. As avariant or in combination, a memory of the microtransponder 7 may recorddigital data which represent an authenticating certificate, optionallyin an encrypted form, that is to say the result of an algorithmiccalculation carried out on information representing the readable script(for example a parity calculation, a CRC (cyclic redundancy check),etc.).

The microtransponder 7 may also simply consist of a hardwired logic chip(integrated logic circuit) for carrying out a specific algorithm on thebasis of input data dependent on the readable script, which aredelivered to it when verifying the authenticity, the result of thisalgorithm making it possible to authenticate the readable script.

In any event, when being read via its individual antenna, themicrotransponder 7 can deliver information for authenticating thereadable script.

FIG. 10 represents a diagram of a reading device 50 and of a method forusing an object 25, 40 protected according to the invention. Thisreading device 50 comprises a power antenna 51, for example with acircular format larger than that of the object 25, 40. When the objectis placed in the magnetic field of this power antenna 51, it is possiblefor the authenticating information delivered by each microprocessor 7via its individual antenna and the electromagnetic coupling loop 14 ofthe matching antenna 12 to be read by the reading device 50, whichincludes suitable computing means, a keyboard 54 and a display screen 53where the readable script 23 protected by each security film 3 can bedisplayed.

The power antenna 51 may be embodied on a table 52 of the reading device50. It should be noted that owing to the matching antenna 12, thelateral positioning of the object 25, 40 with respect to the powerantenna 51 does not need to be precise. The reading range (distancebetween the object and this power antenna 51) may furthermore berelatively large (a few millimeters or even a few centimeters) whichfacilitates the operations and makes them more reliable. The readingdevice 50 and the power antenna 51 may also be used to transmitinformation to each microtransponder 7 (input or control data) or tosupply it with electrical energy via the matching antenna 12 and eachindividual antenna.

The dimensions of the matching antenna 12 are less than those of thepower antenna 51, so that this matching antenna 12 can be contained inthe magnetic field of the power antenna 51 when the object is placed ina reading position on the reading device. The dimensions of the matchingantenna 12 are furthermore as large as possible, in view of the spaceavailable on the object, that is to say the dimensions of the face 26 towhich the matching antenna 12 is applied. The matching antenna 12 hasdimensions which correspond at least substantially to those of theperiphery of the face 26 and in general, as in the embodiments which arerepresented, to those of the periphery of the scripted face 22. Thematching antenna 12 has a radial dimension of more than 1 cm, typicallyof the order of 5 cm, while the individual antenna of a microtransponder7 has a radial dimension of less than 5 mm, typically of the order of 2mm, and the power antenna 51 of a reading device 50 has radialdimensions of more than 5 cm, typically of the order of 10 cm to 20 cm.

EXAMPLE

A security film 3 comprising a microtransponder, and an antenna film 10were formed with the materials and values given in the table below:Printing or material Dimensions composition (mm) SECURITY FILM: Supportsheet 2: ROBEX 515PH polystyrene 88 × 125 marketed by ROYALITE PLASTICS(Italy) Polyurethane layers 4, 5: 2-Component polyurethane 84 × 121varnish S3H/M40-1 grade 77 - marketed by TIFLEX (France) Adhesive layer:Hot melt adhesive No 2-ADTH21 - 84 × 121 Mesh 51 - marketed by TIFLEX(France) Microtransponder: ICL-Link ® PicoPass ® 2 kbits or 2 × 2 × 16kbits marketed by INSIDE 0.180 TECHNOLOGIES (France) ANTENNA FILM:support sheet 11: 50 μm VIFS1 treated polyester 88 × 125 marketed byREXOR (France) Matching Conductive ink 1 Silver ink ref. 5028 - Mesh 82× 119 antenna 77 marketed by Dupont de 12: Nemours (USA) InsulatingUVIPRIM CV cutting base - 83 × 120 varnish Mesh 120 - marketed by TIFLEX(France) Adhesive: Hot melt adhesive No 2-ADTH21 - 88 × 125 Mesh 51 -marketed by TIFLEX (France)The films are applied as represented in FIG. 4 to the recto and verso ofa page of a passport. Information could be recorded in the memory of themicrotransponder 7 and re-read easily with a device as represented inFIG. 10.

The invention may be the subject of a large number of variants inrelation to the embodiments described above purely by way of nonlimitingexamples. In particular, the format of the films 3, 10, 30 may benonrectangular (square, polygonal, rounded, oval, circular, etc.); theshape of the matching antenna 12 may be nonrectangular; the layersforming the films may be varnishes other than polyurethanes, inparticular of the acrylic type or the like; the number of powerantenna(s) 12 and microtransponder(s) 7 per object (sheet or booklet,etc.) or per film 3, 10, 30 may be other than 1; the electromagneticcoupling zones 14 may be of any shape other than square loops (circular,polygonal, chicane, sinuous as described by EP 0826190, U.S. Pat. No.5,955,723, etc.) so long as this shape is favorable for theelectromagnetic coupling. A coupling zone may also be formed simply by acorner or a portion of the matching antenna 12 where the curvature islarge, corresponding to the curvature of the individual antenna of amicrotransponder 7. The films and printing may be formed other than bysilkscreen printing (heliography, offset, smooth-cut, inkjet, etc.).

1-45. (canceled)
 46. A method for protecting readable script formed onat least one face of an object, referred to as a scripted face, in whichreadable script on at least one scripted face of the object is coveredwith a transparent protective film, which adheres to this scripted face,and the object is associated with at least one microcircuit having atleast one antenna for contactless remote reading of authenticatinginformation, which can be delivered by this microcircuit and is designedto permit authentication of at least some of the readable script,wherein: the object is associated with at least one antenna referred toas a matching antenna, formed by printing on a support, this matchingantenna having at least one zone for electromagnetic coupling with anindividual antenna whose dimensions are smaller than those of thematching antenna, at least one transparent protective film referred toas a security film is used, which does not carry a matching antenna butcarries at least one microcircuit with an integrated individual antenna,referred to as a microtransponder, at a predetermined position so thatafter the security film has been placed on a scripted face of theobject, and for at least one position or state of the object: it permitselectromagnetic coupling of the individual antenna with anelectromagnetic coupling zone of a matching antenna associated with theobject, it does not mask any essential part of the readable script, asecurity film is applied and adhered to a corresponding scripted face inorder to cover readable script and so as to permit electromagneticcoupling of the individual antenna of each microtransponder with acoupling zone and a matching antenna, for at least one position or stateof the object, the matching antenna having dimensions designed to permitthe remote transmission of information between the individual antennaand a power antenna of a reading device when the object is placed in thefield of this power antenna.
 47. The method as claimed in claim 46,wherein at least one matching antenna is printed on a printing supportwhich is not a security film carrying at least one microtransponder. 48.The method as claimed in claim 46, wherein at least one matching antennais printed on a face of the object.
 49. The method as claimed in claim48 wherein the matching antenna is subsequently covered with aprotective film.
 50. The method as claimed in claim 46, wherein at leastone matching antenna is printed on a scripted face before applying asecurity film to this scripted face.
 51. The method as claimed in claim46, wherein at least one matching antenna is printed on a face of theobject which is not a scripted face.
 52. The method as claimed in claim46, wherein at least one matching antenna carried by a film of syntheticmaterial referred to as an antenna film is used, and this antenna filmis adhered to a face of the object.
 53. The method as claimed in claim52, wherein the antenna film is applied and adhered to a face of theobject which is not a scripted face.
 54. The method as claimed in claim53, wherein the antenna film is applied and adhered to a face of theobject which is the verso of a sheet of the object whose recto is ascripted face.
 55. The method as claimed in claim 46, wherein at leastone matching antenna is used that is printed with an ink which istransparent to visible light and electrically conductive after drying.56. The method as claimed in claim 52, wherein at least one transferreferred to as an antenna transfer is used, comprising a support sheetcarrying an adhesive antenna film, this antenna transfer being designedto make it possible to apply and adhere the antenna film to a face ofthe object by separating the antenna film from the support sheet. 57.The method as claimed in claim 46, wherein at least one matching antennacomprising an electrical capacitor of adjustable value is used.
 58. Themethod as claimed in claim 46, wherein at least one matching antenna isused which forms a resonant electrical circuit comprising an electricalcapacitor incorporated in a graphic pattern of the antenna film and/orof the object, or superimposed with such a pattern.
 59. The method asclaimed in claim 46, wherein at least one matching antenna printed bysilkscreen printing is used.
 60. The method as claimed in claim 46,wherein at least one given matching antenna is used comprising aplurality of electromagnetic coupling zones for coupling it with aplurality of individual antennas of a plurality of microtransponders.61. The method as claimed in claim 46, wherein a plurality of securityfilms each comprising at least one microtransponder are used for theprotection of readable script on a plurality of scripted faces of theobject.
 62. The method as claimed in claim 46, wherein at least onesecurity film comprising at least one microtransponder incorporated inits thickness is used.
 63. The method as claimed in claim 46, wherein atleast one multilayered security film is used.
 64. The method as claimedin claim 46, wherein at least one security film formed by printing isused, incorporating at least one microtransponder in the thickness ofthe security film when the security film is being formed by printing,between two printed layers.
 65. The method as claimed in claim 46,wherein at least one security film formed by silkscreen printing isused.
 66. The method as claimed in claim 46, wherein at least onetransfer referred to as a protection transfer is used, comprising asupport sheet carrying an adhesive security film, this protectiontransfer being designed to make it possible to apply and adhere thesecurity film to a scripted face of the object by separating thesecurity film from the support sheet.
 67. The method as claimed in claim46, wherein information for authenticating at least some of the readablescript is recorded in at least one memory of at least onemicrotransponder carried by at least one security film covering thisreadable script.
 68. The method as claimed in claim 46, whereinauthenticating information which represents a key and/or an algorithmfor authentication and/or a certificate resulting from an algorithm isrecorded in at least one memory of at least one microtransponder carriedby at least one security film covering readable script.
 69. The methodas claimed in claim 46, wherein at least one microtransponder forming alogic circuit is used.
 70. A device for protecting readable scriptformed on at least one face of an object, referred to as a scriptedface, comprising: at least one transparent protective film, which isintended to adhere to a scripted face while covering readable script,and at least one microcircuit intended to be associated with the object,having at least one antenna for contactless remote reading ofauthenticating information, which can be delivered by the microcircuitand is designed to permit authentication of at least some of thereadable script, wherein it comprises: at least one antenna intended tobe associated with the object, referred to as a matching antenna, formedby printing on a support and having at least one zone forelectromagnetic coupling with an individual antenna whose dimensions aresmaller than those of the matching antenna, at least one transparentprotective film referred to as a security film, which does not carry amatching antenna but carries at least one microcircuit and with anintegrated individual antenna, referred to as a microtransponder, at apredetermined position so that after the security film has been placedon a scripted face of the object, and for at least one position or stateof the object: it permits electromagnetic coupling of the individualantenna with an electromagnetic coupling zone of a matching antennaassociated with the object, it does not mask any essential part of thereadable script, and wherein the matching antenna has dimensionsdesigned to permit the remote transmission of information between theindividual antenna and a power antenna of a reading device when theobject is placed in the field of this power antenna.
 71. The device asclaimed in claim 70, wherein at least one matching antenna is printed ona printing support which is not a security film carrying at least onemicrotransponder.
 72. The device as claimed in claim 70, wherein atleast one matching antenna is printed on a face of the object.
 73. Thedevice as claimed in claim 72, wherein it comprises at least oneprotective film designed to cover at least one printed matching antenna.74. The device as claimed in claim 70, wherein at least one matchingantenna is printed on a scripted face.
 75. The device as claimed inclaim 70, wherein at least one matching antenna is printed on a face ofthe object which is not a scripted face.
 76. The device as claimed inclaim 70, wherein it comprises at least one film of synthetic materialreferred to as an antenna film, which carries at least one printedmatching antenna.
 77. The device as claimed in claim 70, wherein atleast one matching antenna is printed with an ink which is transparentto visible light and electrically conductive after drying.
 78. Thedevice as claimed in claim 76, wherein it comprises at least onetransfer referred to as an antenna transfer, comprising a support sheetcarrying an adhesive antenna film, this antenna transfer being designedto make it possible to apply and adhere the antenna film to a face ofthe object by separating the antenna film from the support sheet. 79.The device as claimed in claim 70, wherein at least one matching antennacomprises an electrical capacitor of adjustable value.
 80. The device asclaimed in claim 70, wherein at least one matching antenna forms aresonant electrical circuit comprising an electrical capacitorincorporated in a graphic pattern of the antenna film and/or of theobject, or superimposed with such a pattern.
 81. The device as claimedin claim 70, wherein it comprises at least one given matching antennacomprising a plurality of electromagnetic coupling zones for coupling itwith a plurality of individual antennas of a plurality ofmicrotransponders.
 82. The device as claimed in claim 70, wherein itcomprises a plurality of security films each comprising at least onemicrotransponder for the protection of readable script on a plurality ofscripted faces of the object.
 83. The device as claimed in claim 70,wherein at least one security film comprises at least onemicrotransponder incorporated in its thickness.
 84. The device asclaimed in claim 70, wherein at least one security film is multilayered.85. The device as claimed in claim 70, wherein at least one securityfilm is formed by printing and incorporates at least onemicrotransponder in its thickness, between two printed layers.
 86. Thedevice as claimed in claim 70, wherein each microtransponderincorporated in a security film has a thickness of less than 0.2 mm andan area of less than 10 mm² in the plane of the security film.
 87. Thedevice as claimed in claim 70, wherein each microtransponderincorporated in a security film has a thickness of between 50μ and 180μ.88. The device as claimed in claim 70, wherein it comprises at least onetransfer referred to as a protection transfer, comprising a supportsheet carrying an adhesive security film, this protection transfer beingdesigned to make it possible to apply and adhere the security film to ascripted face of the object by separating the security film from thesupport sheet.
 89. An object comprising at least one face referred to asa scripted face on which readable script is formed, wherein itcomprises: at least one matching antenna formed by printing on a supportand associated with the object, this matching antenna having at leastone zone for electromagnetic coupling with an individual antenna whosedimensions are smaller than those of the matching antenna, at least onesecurity film which does not carry a matching antenna but carries atleast one microcircuit and with an integrated individual antenna,referred to as a microtransponder, the security film being applied andadhering to a scripted face in order to cover readable script, theposition of each microtransponder being designed so as to permitelectromagnetic coupling of the individual antenna of eachmicrotransponder with a coupling zone of a matching antenna, for atleast one position or state of the object, the matching antenna havingdimensions designed to permit the remote transmission of informationbetween the individual antenna and a power antenna of a reading devicewhen the object is placed in the field of this power antenna, andwherein at least one microtransponder of a security film coveringreadable script is designed to be able to deliver information forauthenticating at least some of the readable script.